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Offline sallam

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Effect of sourdough reproduction rate in flavor profile
« on: February 08, 2018, 11:21:12 AM »
I was browsing this section of the forum when I read a post of TXCraing a little over a year ago where he said:

There has not been much study of sourdough cultures (or breadmaking in general for that matter) outside of the 20-30C range.

So I thought it might be helpful to post this table that I found regarding a detailed study of the growth rate of LAB and yeast in different temperatures ranging from 36f/2c to 93f/34c , posted in TFL forum:

Reproduction Rates of Labs and Yeast   
T(°F)   T (°C)   L. SF I   L. SF II   Yeast     L/Y Ratio
36° F   02° C   0.019    0.016      0.005    3.787
46° F   08° C   0.047    0.043      0.021    2.222
61° F   16° C   0.144    0.150      0.114    1.265
64° F   18° C   0.187    0.198      0.163    1.145
68° F   20° C   0.239    0.259      0.225    1.064
72° F   22° C   0.301    0.332      0.295    1.021
75° F   24° C   0.374    0.416      0.365    1.024
79° F   26° C   0.453    0.508      0.414    1.094
82° F   28° C   0.535    0.598      0.417    1.284
86° F   30° C   0.609    0.672      0.346    1.76
90° F   32° C   0.658    0.706      0.202    3.255
93° F   34° C   0.657    0.671      0.050    13.127

That table shows that LAb actually reproduce faster (almost 3x) than yeast while retarded in 2c than it does in RT ranging from 16c~30c. RT gets even with 2c retarding only when its at 32c. And exceeds it dramatically when it reaches 34c

But there are other factors in play here. As Debra Wink explains here:
Quote
Bacteria contribute acids which flavor dough, but also play a big part in gluten structure and rheology. In the short term acid tightens gluten, contributing to dough strength, but in the long term, it accelerates proteolysis, contributing to its breakdown. And it adds sourness that is not welcome in all breads. You'll find yeast/lift at one end of the starter spectrum and bacteria/sourness at the other. You can't maximize both at the same time; one comes at the expense of the other.

 the one thing that yeast are more sensitive to than lactobacilli is: acetic acid

and Also Wikipedia cites Debra Wink's post here:
Quote
A drier and cooler starter has less bacterial activity and more yeast growth, which results in the bacterial production of more acetic acid relative to lactic acid. Conversely, a wetter and warmer starter has more bacterial activity and less yeast growth, with more lactic acid relative to acetic acid

That is probably why longer retarding results in a better tangy flavor profile than long RT fermentation. But one has to strike a balance, otherwise the protein/gluten is all lost and the dough turns into unmangeable soup, as Peter Rienhart puts it.

As for starter feeding, from my experiments I found no difference between multiple feedings and one single larger feeding. Its more convenient to replace 3 feedings of 1:1:1 with one feeding of 1:3:3. Same time, same amout of flour, same starter activity, only more convenient.

I usually refrigerate my starter immediately after refreshing, then take out of fridge the night before mixing a preferment. That way, it is always at its peak when needed, without waiting to refresh it at all before using.

I use all of my starter in making the levain. Once the preferment/levain is mixed, I take an equal weight of the starter back in its jar, and immediately store in the fridge again for my next weekly dough.
« Last Edit: February 08, 2018, 11:30:23 AM by sallam »
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Offline TXCraig1

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #1 on: February 08, 2018, 02:33:09 PM »
I was browsing this section of the forum when I read a post of TXCraing a little over a year ago where he said: ...
     so I thought it might be helpful to post this table that I found regarding a detailed study of the growth rate of LAB and yeast in different temperatures ranging from 36f/2c to 93f/34c , posted in TFL forum:

There has not been much study of sourdough cultures (or breadmaking in general for that matter) outside of the 20-30C range.

Sallam, all of this is covered here: https://www.pizzamaking.com/forum/index.php?topic=41039.0 including the study (Gänzle et al. (1998)) that presented the formulas used to make that table - inciudentally, they are the same formulas that  I used as the basis for the sourdough prediction model: https://www.pizzamaking.com/forum/index.php?topic=22649.0

What tends to get missed in this discussion is that there is another dimension to the analysis. We often read things like "cold favors LAB over yeast," and while this is true as the chart in your post shows, "favoring" is not the same as "increasing," and "faster" is not the same thing as "faster." Yes, at refrigeration temps, yeast may reproduce 3-4 times faster than LAB as compared to room temp (call it 20C), but what it ignores is that LAB grow 12X faster at 20C than 2C. In fact, growth comes to a near stand still at refrigeration temps. That's why refrigeration temps are <5C.

I actually asked Dr. Gänzle about how long it takes a dough without added LAB to reach meaningful numbers to which he replied:

Quote
I never read anything about how long the lactics take to grow to reasonable numbers in the fridge, I assume it takes at least twice as long compared to room temperature.

Note to my point that there isn't much written on the subject from a scientific perspective - just stuff written by folks who really don't understand the science and misinterpret the idea of cold favoring LAB over yeast.
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Offline sallam

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #2 on: February 08, 2018, 03:44:43 PM »
Craig,
Thanks very much for directing me to your respectful and educational research.

Sallam, all of this is covered here: https://www.pizzamaking.com/forum/index.php?topic=41039.0 including the study (Gänzle et al. (1998)) that presented the formulas used to make that table

One particular point made by Dr.Gänzle in his reply to your question drew my attention:
Quote
Refrigeration does not inhibit enzyme activity (amylase, protease, a few others). I assume that much of the flavour impact of long fermentation results from more time given to cereal enzymes to break down starch and protein.

Perhaps that is why when I retard my dough for 3 days or more I get that delicious deep flavor that I never encountered when fermenting in RT. Perhaps its those cereal enzymes that we really need, to get such wonderful flavor/aroma, not LAB? if not so, it must be anyhow something other than LAB, since as you concluded, LAB multiply much more in RT, so something else is responsible for that deliciousness of long retarding.. no?
« Last Edit: February 08, 2018, 03:50:12 PM by sallam »
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Offline TXCraig1

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #3 on: February 08, 2018, 03:53:33 PM »
Note his follow-up to that response. By "inhibited," he meant they were not inactivated. Enzyme activity is definitely showed by cooler temperatures.

Quote
with "not inhibited" I meant slower but not completely inactive...

Enzyme activity typically doubles (or halves) with a 10C change in temperature. At 2C, and you can expect to have roughly 25% of the enzyme activity as at 20C, AOTBE.
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Offline TXCraig1

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #4 on: February 08, 2018, 03:59:38 PM »
Perhaps that is why when I retard my dough for 3 days or more I get that delicious deep flavor that I never encountered when fermenting in RT. Perhaps its those cereal enzymes that we really need, to get such wonderful flavor/aroma, not LAB? if not so, it must be anyhow something other than LAB, since as you concluded, LAB multiply much more in RT, so something else is responsible for that deliciousness of long retarding.. no?

It's a combination of yeast, enzymes, and LAB. A main point in the fermentation post is that maybe you can get there with cold ferment but it takes 4X as long.

Also, when people write about the benefits of long cold retarding, they generally aren't comparing the results to long RT ferments (I don't think I've ever seen such a comparison). Rather, they are comparing to a typical emergency-type dough. Of course a long cold ferment tastes better.
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Offline sallam

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #5 on: February 08, 2018, 04:09:21 PM »
Craig, I've just visited your website at http://www.lindbergs.us/
What a stunning collection of pizza photos.
I wonder what is your steps for making your pizza dough. Would you share your recipe please, or point me to a post detailing your steps for producing such wonderful pizzas ?
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Offline TXCraig1

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #6 on: February 08, 2018, 04:15:38 PM »
Craig, I've just visited your website at http://www.lindbergs.us/
What a stunning collection of pizza photos.
I wonder what is your steps for making your pizza dough. Would you share your recipe please, or point me to a post detailing your steps for producing such wonderful pizzas ?

Thank you for the kind words. This post describes how I make my pizza fine detail: https://www.pizzamaking.com/forum/index.php?topic=20479.0

About the only things I do differently is that I tend to ferment a bit cooler (61-62F), use a bit more culture (1.9%-2.1% depending on the ambient temp), use wood dough boxes now rather than plastic tubs, and divide the 48 hour fermentation time up as 36 hours in bulk and 12 hours in balls (mostly driven by the use of pine wood boxes which tend to overly dry the bottom of the dough balls if you use them for much longer than 12 hours).
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Offline sallam

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #7 on: February 11, 2018, 02:35:47 AM »
Thanks very much Craig for all the fine details. There is much to learn from your posts.

Thank you for the kind words. This post describes how I make my pizza fine detail: https://www.pizzamaking.com/forum/index.php?topic=20479.0

About the only things I do differently is that I tend to ferment a bit cooler (61-62F), use a bit more culture (1.9%-2.1% depending on the ambient temp), use wood dough boxes now rather than plastic tubs, and divide the 48 hour fermentation time up as 36 hours in bulk and 12 hours in balls (mostly driven by the use of pine wood boxes which tend to overly dry the bottom of the dough balls if you use them for much longer than 12 hours).

I've been trying different figures with your sourdough prediction spreadsheet, that I've downloaded from: https://docs.google.com/spreadsheets/d/1UEj7IApIauBjj_9d3jdWrbjOjnWu5FICcgAFZY6p8Oc/edit#gid=0

I have 3 questions please:

1- Your technique is considered a one stage ferment? because when I entered the numbers in your method (48 hours and 62f) it gave me 2.97% , am I missing something?

2- Why do you have to ferment in 62f ? what are the advantages over ambient RT? what flavor profile do you get?

3- Where I live its around 80f. Based on your prediction model, If I was to ferment in that temperature, I should use 0.2% starter to ferment in 27 hours. What if I punch down to degas the dough, to buy me some more ferment time (and hopefully more tangy flavor)? do you think this would work? or is 0.2% too small to protect the dough from contamination?
« Last Edit: February 11, 2018, 03:33:12 AM by sallam »
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Offline TXCraig1

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #8 on: February 11, 2018, 01:53:15 PM »
I don't know what I was thinking when I typed that. It should say 62-64F. I used to ferment 64-65F, but I put in a new, very high efficiency AC, and I've been keeping the house a couple degrees cooler and the temp in the ice chest I ferment in dropped a couple degrees with the lower ambient. I ferment at that temp because it's easy for me to hold the temp there in the cooler, and I prefer it to the dough I get when I do it all at my ambient (74-75F). It's also more forgiving of differences in culture activity than fermenting at ambient.

I've never gone that low, but I think 0.2% would be fine. That's way more yeast and LAB than are naturally in the flour. I think it's going to be hard to get much tang at 80F, particularly in 27 hours. The LAB will be mostly making lactic acid. Low 60's for 3 days gives me San Francisco levels of tang. You never know until you try however. All cultures are different. I'm not a fan of punching down pizza dough. I never do it and don't have any experience to share in that regard.

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Offline sallam

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #9 on: February 13, 2018, 02:34:18 AM »
I've never gone that low, but I think 0.2% would be fine. That's way more yeast and LAB than are naturally in the flour.

You're right. It worked fine, no contamination. It took 24 hours to double, and a portion was baked 3 hours later with good results. Another portion was baked 12 hours later (total 36 hours) but it wasn't as good: no oven rise, and no color. Must have way over-proofed ?

Do you think balling, once dough reaches 2x, then retarding in fridge is a good idea? I'm thinking that perhaps retarding would allow me to have pizza balls ready whenever I want to bake with, plus it could perhaps encourage some acetic acid tangy flavor? you probably tried this before? if so, what was the outcome in regards to flavor, color and oven rise? and how many days such ripe-dough balls can keep in a fridge?

Low 60's for 3 days gives me San Francisco levels of tang.

3 days? wouldn't that make the dough over-ferment? do you then get oven rise?
When I kept mine for just an extra 12 hours, it produced no oven rise at all.
« Last Edit: February 13, 2018, 02:36:02 AM by sallam »
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Offline TXCraig1

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #10 on: February 13, 2018, 08:49:36 AM »
Do you think balling, once dough reaches 2x, then retarding in fridge is a good idea? I'm thinking that perhaps retarding would allow me to have pizza balls ready whenever I want to bake with, plus it could perhaps encourage some acetic acid tangy flavor? you probably tried this before? if so, what was the outcome in regards to flavor, color and oven rise? and how many days such ripe-dough balls can keep in a fridge?

I'm not a fan of cold fermenting/retarding sourdough. If tang is your first priority and you're willing to give up some texture and tenderness, maybe it's worth experimenting. I'd ball well before 2X because risen dough takes a LONG time to cool in the fridge. My guess is that it would be overblown before it cools enough to significantly retard fermentation. Personally, I don't like to see much of any rise in by dough when I ball.

Quote
3 days? wouldn't that make the dough over-ferment? do you then get oven rise?
When I kept mine for just an extra 12 hours, it produced no oven rise at all.

Adjust the yeast quantity down such that it's not overfermented.
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Offline bradtri

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #11 on: February 13, 2018, 10:44:44 AM »

Do you think balling, once dough reaches 2x, then retarding in fridge is a good idea? I'm thinking that perhaps retarding would allow me to have pizza balls ready whenever I want to bake with,
Sallam- I have several times used the refrigerator to hold SD doughballs from 1-4 days for later use.  I use aluminum sheet pans for my dough balls so perhaps that helps them cool down quickly.  Otherwise you might want to consider 30-60 minutes in the freezer to get them chilled quickly and then move to fridge. 
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Offline sallam

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #12 on: February 13, 2018, 03:09:07 PM »
you might want to consider 30-60 minutes in the freezer to get them chilled quickly and then move to fridge.

Great idea, thanks. I'll do that. I remember that once, years ago, I put dough balls in the freezer for 24 hrs following a 3-day CF, and it gave the pies amazing rich tangy flavor.
« Last Edit: February 13, 2018, 03:54:06 PM by sallam »
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Offline bradtri

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #13 on: February 13, 2018, 03:39:29 PM »
Great idea, thanks. I'll do that. I remembers that once, years ago, I put dough balls in the freezer for 24 hrs following a 3-day CF, and it gave the pies amazing rich tangy flavor.

I don't know that I'd freeze SD dough completely.   I was just thinking of speeding up the chilling process.   I really don't think freezing would ever do anything positive for flavor and I'm not even sure the SD would survive.
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Offline sallam

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #14 on: February 22, 2018, 05:23:21 PM »
About the only things I do differently is that I tend to ferment a bit cooler (61-62F), use a bit more culture (1.9%-2.1% depending on the ambient temp)

My last batch didn't ferment in the expected time. Perhaps because I refreshed my starter only once before using it in the dough?

I noticed that the more I repeat feeding my starter in RT, the higher it gets. First feeding it rises 2x before it collapses, second feeding it can reach 3x before it collapses.

you mentioned that you use your starter when its fully active. ..
- Do you keep your starter in the fridge?
- and to make it fully active, do you refresh it in RT once?, twice? or 3 times to get it fully active before using it?
- and how high should your starter reach before collapsing to earn your trust as a "fully active" starter ready to be used in your pizza napoletana dough?
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Offline TXCraig1

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #15 on: February 22, 2018, 05:27:30 PM »
I keep it in the fridge if I'm not going to use it for more than a week or two. On the counter I feed it at least every other day. In the fridge, I've gone as long as 6 months without feeding. Generally speaking, after taking it out of the fridge, 2-3 feedings seems to get it back in shape. I usually feed it in the morning of the day I plan to use it regardless of when it was last fed. It will more than double and maybe begin to fall a bit by the time I use it.
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Offline sallam

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #16 on: February 24, 2018, 04:54:13 PM »
I keep it in the fridge if I'm not going to use it for more than a week or two. On the counter I feed it at least every other day.

I didn't know you could keep a starter in RT that long between feedings.
Is it 100% hyrdation?
What is your feeding ratio? not 1:1:1 i guess.. because mine starts to get hungry after only 6~8 hours
« Last Edit: February 24, 2018, 04:56:14 PM by sallam »
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Offline TXCraig1

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #17 on: February 24, 2018, 05:00:53 PM »
I haven't measured in years. I basically dump about 70% out then add enough water and flour to bring it back to the original quantity and ~100%HR consistency.
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Offline sallam

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #18 on: February 25, 2018, 08:44:38 AM »
I haven't measured in years. I basically dump about 70% out then add enough water and flour to bring it back to the original quantity and ~100%HR consistency.
That's about 1:2:2
Interesting. My starter would start to collapse the same day, even half day.
- What state is your starter when you feed it every other day in RT? at peak, started to fall, or totally fallen? any hooch?
- and how often do you use it in dough?
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Offline the1mu

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Re: Effect of sourdough reproduction rate in flavor profile
« Reply #19 on: February 25, 2018, 10:59:32 AM »
Don’t forget that temperature plays a role here as well. If the starter is kept cooler it obviously will be slower. I feed my at 20% inoculation to achieve a ripe dough in 12-14 hours at 68-70°.  I go down to 10% for 24 hours. If my kitchen is cooler (as it is now), say 62-64, I bump it up to almost 30% for the 12 hour range.

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